Fluidistor

ABSTRACT

A fluidistor of the type comprising an inlet, at least two outlets, and an intermediate passage including at least one control chamber. The transition region between the inlet and the control chamber is designed to provide unstable flow to the control chamber. This increases the amplification of the device by reducing the control energy required to switch the output from one outlet to another. The unstable flow to the control chamber is caused by wedgelike shoulder means projecting substantially perpendicular to the direction of flow at the transition region from inlet to control chamber. The wedgelike shoulder means has a small dimension in the direction of flow as compared to the dimension perpendicular to the direction of flow. The transition region from the control chamber to the outlet is also sharply defined for the same reasons.

United States Patent [72] lnventor Per Svante Bahrton 182 75 Stocksund, l1 Villavagen, Sweden [21 Appl. No. 796,484 [22] Filed Feb. 4, 1969 [45] Patented Sept. 28, 1971 [32] Priority Feb. 6, 1968 [33] Sweden 31 1537/68 [54] FLUIDISTOR 6 Claims, 2 Drawing Figs.

[52] U.S. Cl 137/81.5 [51] Int. Cl Fl5c l/04 [50] Field ofSearch 137/81.5

[56] References Cited UNITED STATES PATENTS 3,420,253 1/1969 Griffin 137/81.5 3,456,665 7/1969 Pavlin l37/81.5 3,486,520 12/1969 Hyer et al. 137/8l.5 3,500,849 3/1970 McLeod, .lr. 137/81.5

Primary Examiner-Samuel Scott Att0rney-Fred C. Philpitt ABSTRACT: A fluidistor of the type comprising an inlet, at least two outlets, and an intermediate passage including at least one control chamber. The transition region between the inlet and the control chamber is designed to provide unstable flow to the control chamber. This increases the amplification of the device by reducing the control energy required to switch the output from one outlet to another. The unstable flow to the control chamber is caused by wedgelike shoulder means projecting substantially perpendicular to the direction of flow at the transition region from inlet to control chamber. The wedgelike shoulder means has a small dimension in the direction of flow as compared to the dimension perpendicular to the direction of flow. The transition region from the control chamber to the outlet is also sharply defined for the same reasons.

PATYENTED SEP28 Ian 3 6 08 l 57 3 FLUIDISTOR The present invention relates to a fluidistor of the type comprising an inlet, at least two outlets and an intermediate passage, including at least one control chamber, each control chamber being adapted to be supplied with a control signal serving to cause a fluid passing through the fluidistor to leave it through one or more selected outlets.

The main object of the invention is to provide a fluidistor of the kind above specified, having such a design that its field of use will become very broad and generic.

Another object of the invention is to provide a fluidistor which is adapted to be used for liquids as well as for gaseous fluids.

A further object of the invention is to provide a fluidistor which, following no or insignificant modifications, permits the flow speed to vary within wide limits.

Still another object of the invention is to provide a fluidistor that can be controlled by a variety of different control means.

The invention has also for its purpose to provide a fluidistor pennitting a low control power to-be used for controlling the flow of a fluid passing through the fluidistor at a high energy, i.e. at a high-speed and/orata high-static pressure.

According to the invention the fluidistor is primarily characterized in that at the transition between the inlet and said intermediate passage there is provided a restriction adapted to generate or amplify a vortex in a control chamber for the purpose of changing the direction of flow of said fluid.

According to a preferred embodiment of the invention said restriction is constituted by a rib, a flange or similar means projecting into the inlet. The surface of the restriction member defining its upstream wall forms a considerable angle, preferably about 90, with the main direction of flow in the inlet, said direction being substantially parallel to'the longitudinal axis of the inlet.

In many cases it is suitable to dimension the rib, flange or similar means so that, in the main direction of the flow of the working fluid, it will have a small width as compared to its extension perpendicular to said direction of flow and to the plane in which the flow is moved when diverted from one outlet to another.

Another characteristic feature of the invention is that the distance between the edge of the restriction closest to the longitudinal axis of the inlet and said axis is approximately equal to the distance between said axis and the portion of the fluidistor forming a transition between a control chamber and the corresponding outlet. The last-mentioned portion of the fluidistor should in turn be located upstream of the adjacent portion of the wall of the control chamber.

The invention will now be described in greater detail, reference being had to the accompanying diagrammatic drawing illustrating one embodiment of the invention.

FIG. 1 is a perspective view showing a fluidistor designed according to the invention and comprising one inlet and two outlets.

FIG. 2 is a horizontal sectional view illustrating the flow pattern in the fluidistor of FIG. 1 when set for controlled flow through one of its two outlets.

Reference numeral generally designates a fluidistor here shown as comprising a block 11 with one inlet 12 and two outlets l3 and 14. For simplifying the manufacture two opposite wall portions of the fluidistor are presumed to consist of two parallel cover plates, one of which, identified as 110, has been shown in FIG. 1. FIG. 1 also illustrates threaded holes 11' for receiving screws adapted to secure the other cover plate, not shown, to block 11.

Between inlet 12 and each outlet 13 and 14, respectively, there is provided a control chamber or vortex chamber 15, 16. Reference numerals 17 and 18 designate edges defining the transitions between the control chambers and 16, and the respective outlets 13 and 14. Each control chamber has connected thereto a conduit 19 and 20, respectively, containing a valve means 21 and 22, respectively. In accordance with the main characteristic of the invention, at the transition between inlet 12 and control chambers 15 and 16 there is provided a restriction which, in the embodiment shown, is formed by two projections 23, 24 extending from two opposite walls of the inlet. The purpose of this restriction will be explained below.

The function of the fluidistor will now be explained with reference to FIG. 2. The working fluid is introduced through inlet 12. If symmetrical conditions prevail in the two control chambers 15 and 16, i.e. if valve member 21 and 22 are both open or closed, as the case may be, it may occur that the flow of the fluid is either split between the two outlets 13 and 14 or passed quite at random through either of them. However, by setting up a pressure difference between the two control chambers it is possible positively to divert the fluid through a selected outlet. In the control chambers the passing working fluid will due to an ejector effect create a partial vacuum. Considering, by way of example, control chamber 15 and assuming that valve 21 in conduit 19 is closed it is obvious that the reduced pressure in said chamber will be maintained, whereas if the value is open the pressure difference will continuously be compensated. The fluid surrounding the fluidistor 10 may be the controlling fluid and it may operate at the pressure of the ambient fluid which might be the atmosphere. It should, however, be emphasized that the general condition for control is that a pressure difference can be set up between the two chambers, and that this may be effected by use of any suitable means. One method for creating such a pressure difference is positively to generate an excess pressure in one of the control chambers while maintaining a lower pressure in the other chamber. Said lower pressure could be that of the ambient. At any rate, in the case here under discussion, it is assumed that valve 21 is closed whereas valve 22 is open. In control chamber 16 the pressure will thus be continuously compensated whereas a reduced pressure will prevail in chamber 15.

In chamber 15 the projection 23 will cause a vortex generally moving in a clockwise direction as indicated by arrows. This means that at the entrance orifice to outlets l3 and 14 defined by edges 17 and 18 the working fluid will be subjected to the influence of a component of motion directed downwardly in FIG. 2 and against the outer walls of chamber 15 and outlet 13. Hereby the fluid will be directed into outlet 13. Should, in accordance with any of the methods above generally referred to, the pressure difference be reversed, the conditions just described will instead appear in chamber 16 so that the working fluid will be switched over to outlet 14. Obviously, the fluidistor will function in the same general manner as a flip-flop circuit or bistable switching circuit.

It is known per se in fluidistors to use control chambers of the kind here described. However, the presence of a restriction defined by projections 23 and 24 is a significant characteristic of this invention as is the dimensioning of those portions of the fluidistor defining the transitional region at the entrance to outlets l3 and 14, i.e. the region adjacent edges 17 and 18.

The vortex in the respective control chamber produced or amplified by projections 23 and 24 will render the fluidistor a reliable switching function and make it easily controllable.

As far as the location and the exact shape of the restriction is concerned, those parameters may be varied in response to the actual conditions. However, in accordance with an important feature of the invention the restriction must have such a profile, that an abrupt change in the flow pattern is caused at the transition between the inlet and the control chambers. In this way the desired vortex generation or amplification in those chambers is secured. In most cases the transverse length of the restriction amounts to between 10 and 40 percent of the distance between the inner wall of the inlet and the center axis thereof. A restriction which significantly decreases the resulting cross-sectional area in the inlet but is streamlined or in other way elongated so that is main effect on the working fluid is an increase in flow speed is outside the scope of the present invention. Also in other respects the geometrical shape and design of the various components of the fluidistor may be varied to a great extent. It has already been mentioned that a general condition for control is that a pressure difference should be set up between the two control chambers. Also as far as the nature of the control fluid is concerned there are many possibilities. In this connection it should be noted that the control fluid may have either the same state of aggregate as the working fluid or another state of aggregate. The working fluid may be either a liquid or a gas. The number of outlets of the fluidistor as well as their directions may also be varied in view of the local conditions and several fluidistor units may be entirely or partially combined into a common device. Finally, it serves to be mentioned that the fluidistor according to this invention can be controlled by means of continuous control signals as well as by means of control pulses of short duration.

What is claimed is:

l. A fluidistor having an inlet, at least two outlets and an intermediate passage containing at least one control chamber, each said control chamber being adapted to be supplied with a control signal, in the form of a control fluid flow, serving to direct a working fluid, passing through said fluidistor from said inlet to a selected outlet,

characterized in that a transition region between said inlet and said control chamber, and upstream of said control chamber, there are provided wedgelike shoulder means projecting inwardly towards the longitudinal axis of said inlet for the purpose of increasing the coefficient of amplification in the switching of the direction of flow of said working fluid, the junction of said shoulder means and said inlet being sharply defined.

2. A fluidistor as claimed in claim 1, characterized in that upstream wall surfaces of said shoulder means are substantially perpendicular to the main direction of flow of said working fluid in said inlet or with a longitudinal axis of said inlet.

3. A fluidistor as claimed in claim 2, characterized in that said shoulder means have a small width in the main direction of flow of said working fluid as compared to its extension perpendicular to said direction of flow and to the plane in which switching takes place.

4. A fluidistor as claimed in claim 1, characterized in that the minimum distance between said shoulder means and the longitudinal axis of said inlet is approximately equal to the distance between said longitudinal axis of said inlet and the portion of the fluidistor defining a transition between said control chamber and a corresponding outlet.

5. A fluidistor as claimed in claim 4, characterized in that said portion of said fluidistor, defining the transition between said control chamber and its related outlet, is sharply defined, comprising in edge facing the direction of working fluid flow.

6. A fluidistor as claimed in claim 4, characterized in that the transition between a control chamber and its related outlet is located upstream of the adjacent portion of the wall of said control chamber. 

1. A fluidistor having an inlet, at least two outlets and an intermediate passage containing at least one control chamber, each said control chamber being adapted to be supplied with a control signal, in the form of a control fluid flow, serving to direct a working fluid, passing through said fluidistor from said inlet to a selected outlet, characterized in that a transition region between said inlet and said control chamber, and upstream of said control chamber, there are provided wedgelike shoulder means projecting inwardly towards the longitudinal axis of said inlet for the purpose of increasing the coefficient of amplification in the switching of the direction of flow of said working fluid, the junction of said shoulder means and said inlet being sharply defined.
 2. A fluidistor as claimed in claim 1, characterized in that upstream wall surfaces of said shoulder means are substantially perpendicular to the main direction of flow of said working fluid in said inlet or with a Longitudinal axis of said inlet.
 3. A fluidistor as claimed in claim 2, characterized in that said shoulder means have a small width in the main direction of flow of said working fluid as compared to its extension perpendicular to said direction of flow and to the plane in which switching takes place.
 4. A fluidistor as claimed in claim 1, characterized in that the minimum distance between said shoulder means and the longitudinal axis of said inlet is approximately equal to the distance between said longitudinal axis of said inlet and the portion of the fluidistor defining a transition between said control chamber and a corresponding outlet.
 5. A fluidistor as claimed in claim 4, characterized in that said portion of said fluidistor, defining the transition between said control chamber and its related outlet, is sharply defined, comprising an edge facing the direction of working fluid flow.
 6. A fluidistor as claimed in claim 4, characterized in that the transition between a control chamber and its related outlet is located upstream of the adjacent portion of the wall of said control chamber. 